Apparatus for mounting a rack in a dishwasher

ABSTRACT

A dishwasher includes a tub at least partially defining a treating chamber, a rack for holding utensils for treatment within the treating chamber, a first wheel coupled with the tub, a second wheel coupled with the rack, and a track. The track can have first and second channels in a back-to-back relationship for respectively receiving the first and second wheels to slidably mount the rack to the tub.

BACKGROUND OF THE INVENTION

Dishwashers include a treating chamber in which utensils are placed to be washed according to an automatic cycle of operation. Typically, at least one rack is located in the treating chamber for holding utensils to be cleaned. In dishwashers where the treating chamber is accessible through a moveable door, one or more rack(s) can be slidably mounted within the treating chamber in such a manner that at least a major portion of the rack(s) can be slid substantially beyond the treating chamber to ease the loading of the racks.

SUMMARY OF THE INVENTION

The invention relates to an apparatus including a dishwasher having a tub at least partially defining a treating chamber and having at least one side, a rack for holding utensils for treatment within the treating chamber, a first wheel mounted to the at least one side of the tub, a second wheel mounted to the rack, and a track having a first C-shaped channel receiving the first wheel and a second C-shaped channel receiving the second wheel to slidably mount the rack to the tub, with the first and second C-shaped channels in a back-to-back relationship.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic cross-sectional view of an automatic dishwasher;

FIG. 2 is a front perspective view of the automatic dishwasher 10 of FIG. 1 illustrating an upper rack mounted to the dishwasher by a rail system according to one embodiment of the invention;

FIG. 3 is a front view of a portion of the dishwasher of FIG. 2, illustrating a rail assembly of the rail system which mounts the upper rack to the dishwasher;

FIG. 4 is an exploded view of the rail assembly from FIG. 3;

FIG. 5 is a cross-sectional view through the rail assembly from FIG. 3;

FIG. 6 illustrates the upper rack and rail system in a first or cycle position;

FIG. 7 illustrates the relative position of wheels within the rail assembly in the first/cycle position of FIG. 6;

FIG. 8 illustrates the upper rack and rail system in a second or loading position; and

FIG. 9 illustrates the relative position of wheels within the rail assembly in the second/loading position of FIG. 8.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The invention is generally directed toward rack mounting arrangements for dishwashers, and more particularly to rail systems which allow a rack to slide in and out of a treating chamber in the dishwasher. FIG. 1 is a schematic cross-sectional view of an automatic dishwasher 10 according to one embodiment of the invention, the dishwasher 10 having a cabinet 12 defining an interior. Depending on whether the dishwasher 10 is a stand-alone or built-in, the cabinet 12 may be a chassis/frame with or without panels attached, respectively. The dishwasher 10 shares many features of a conventional automatic dishwasher, which will not be described in detail herein except as necessary for a complete understanding of the invention.

A controller 14 may be located within the cabinet 12 and may be operably coupled with various components of the dishwasher 10 to implement one or more cycles of operation. A control panel or user interface 16 may be provided on the dishwasher 10 and coupled with the controller 14. The user interface 16 may include operational controls such as dials, lights, switches, and displays enabling a user to input commands, such as a cycle of operation, to the controller 14 and receive information.

A tub 18 is located within the cabinet 12 and at least partially defines a treating chamber 20 with an access opening in the form of an open face. A cover, illustrated as a door 22, may be hingedly mounted to the cabinet 12 and may move between an opened position, as shown in FIG. 2, wherein the user may access the treating chamber 20, and a closed position, as shown in FIG. 1, wherein the door 22 covers or closes the open face of the treating chamber 20.

Utensil holders in the form of upper and lower racks 24, 26 are located within the treating chamber 20 and receive utensils for treatment. The racks 24, 26 are mounted for slidable movement in and out of the treating chamber 20 for ease of loading and unloading. As used in this description, the term “utensil(s)” is intended to be generic to any item, single or plural, that may be treated in the dishwasher 10, including, without limitation; dishes, plates, pots, bowls, pans, glassware, and silverware. While not shown, additional utensil holders, such as a silverware basket on the interior of the door 22, may also be provided.

A spraying system 28 may be provided for spraying liquid into the treating chamber 20 and is illustrated in the form of an upper sprayer 30, a mid-level sprayer 32, a lower rotatable spray arm 34, and a spray manifold 36. The upper sprayer 30 may be located above the upper rack 24 and is illustrated as a fixed spray nozzle that sprays liquid downwardly within the treating chamber 20. Mid-level rotatable sprayer 32 and lower rotatable spray arm 34 are located, respectively, beneath upper rack 24 and lower rack 26 and are illustrated as rotating spray arms. The mid-level spray arm 32 may provide a liquid spray upwardly through the bottom of the upper rack 24. The lower rotatable spray arm 34 may provide a liquid spray upwardly through the bottom of the lower rack 26. The mid-level rotatable sprayer 32 may optionally also provide a liquid spray downwardly onto the lower rack 26, but for purposes of simplification, this will not be illustrated herein.

The spray manifold 36 may be fixedly mounted to the tub 18 adjacent to the lower rack 26 and may provide a liquid spray laterally through a side of the lower rack 26. The spray manifold 36 may not be limited to this position; rather, the spray manifold 36 may be located in virtually any part of the treating chamber 20. While not illustrated herein, the spray manifold 36 may include multiple spray nozzles having apertures configured to spray wash liquid towards the lower rack 26. The spray nozzles may be fixed or rotatable with respect to the tub 18. Suitable spray manifolds are set forth in detail in U.S. Pat. No. 7,445,013, filed Jun. 17, 2003, and titled “Multiple Wash Zone Dishwasher,” and U.S. Pat. No. 7,523,758, filed Dec. 30, 2004, and titled “Dishwasher Having Rotating Zone Wash Sprayer,” both of which are incorporated herein by reference in their entirety.

A liquid recirculation system may be provided for recirculating liquid from the treating chamber 20 to the spraying system 28. The recirculation system may include a sump 38 and a pump assembly 40. The sump 38 collects the liquid sprayed in the treating chamber 20 and may be formed by a sloped or recessed portion of a bottom wall 42 of the tub 18. The pump assembly 40 may include both a drain pump 44 and a recirculation pump 46.

The drain pump 44 may draw liquid from the sump 38 and pump the liquid out of the dishwasher 10 to a household drain line 48. The recirculation pump 46 may draw liquid from the sump 38 and pump the liquid to the spraying system 28 to supply liquid into the treating chamber 20. While the pump assembly 40 is illustrated as having separate drain and recirculation pumps 44, 46 in an alternative embodiment, the pump assembly 40 may include a single pump configured to selectively supply wash liquid to either the spraying system 28 or the drain line 48, such as by configuring the pump to rotate in opposite directions, or by providing a suitable valve system. While not shown, a liquid supply system may include a water supply conduit coupled with a household water supply for supplying water to the sump 38. A heating system having a heater 50 may be located within or near a lower portion of the tub 18 for heating liquid contained therein.

FIG. 2 is a front perspective view of the automatic dishwasher 10 of FIG. 1, with the door 22 in an open position. The tub 18 includes spaced opposing side walls 52. At least the upper rack 24 is coupled to the tub 18 by a rail system 54 for mounting the upper rack 24 to the side walls 52 of the tub 18. At least the side walls 52 of the tub 18 can be flexible, for example, by limiting the underlying support structure (not shown) in the vicinity of the rail system 54, thereby, allowing the side walls 52 to flex, and/or by being constructed of in a flexible thin panel of material, such as polypropylene or stainless steel.

The rail system 54 comprises a pair of rail assemblies 56, one associated with each side wall 52 of the tub 18 and which couples one lateral side of the rack 24 to the tub 18. While not described herein, the lower rack 26 can also be coupled to the side walls 52 of the tub 18 by a similar rail system 54. The racks 24, 26 are moveable between a first or cycle position in which the racks 24, 26 are received within the treating chamber 20 and the door 22 can be closed in order to begin a cycle of operation, and a second or loading position in which the door 22 is open and the racks 24, 26 are slid at least partially out of the treating chamber 20 for ease of loading and unloading utensils from the racks 24, 26. In FIG. 2, the lower rack 26 is shown in the first/cycle position, and the upper rack 24 is shown in the second/loading position.

FIG. 3 is a front view of a portion of the dishwasher 10, illustrating the upper rack 24 mounted to the dishwasher 10 by the rail assembly 56. Each rail assembly 56 includes at least one first wheel 58 mounted to the side wall 52 of the tub 18 and at least one second wheel 60 mounted to the rack 24, and a track 62 which is configured to receive both wheels 58, 60 to slidably mount the rack 24 to the tub 18. The track 62 can have a first C-shaped channel 64 and a second C-shaped channel 66 arranged in a back-to-back relationship, which each C-shaped channel 64, 66 adapted to receive one of the wheels 58, 60.

In the illustrated embodiment, each rail assembly 56 further includes one or more tub mounting bracket(s) 68 and a rack mount 70. The tub mounting bracket(s) 68 are fixedly mounted to the side wall 52 of the tub 18, and mount the first wheel 68, which is received within the first C-shaped channel 64 of the track 62. The rack mount 70 attaches to the rack 24 and carries the second wheel 60, which is received within the second C-shaped channel 66 of the track 62. The C-shaped channels 64, 66 of the track 62 can be separated by a partition 72 extending between the channels 64, 66, thereby dividing the channels 64, 66 into separate raceways for the wheels 58, 60.

FIG. 4 is an exploded view of the rail assembly 56 from FIG. 3. The first C-shaped channel 64 can be defined by a first rail 74 and the second C-shaped channel 66 can be defined by a second rail 76. In the illustrated embodiment, the first and second rails 76 have a similar construction, except that they are mirror image of each other when installed; thus, the rails 74, 76 will not be described separately herein, except where necessary for a full understanding of the embodiment of the invention. Each rail 74, 76 can include an elongated body having a generally vertical middle wall 78, an upper L-shaped wall 80, and a lower L-shaped wall 82 extending from and along the middle wall 78, such that a cross-section of the rail 74, 76 has a C-shape. An elongated opening 84 is positioned opposite the middle wall 78, between the L-shaped walls 80, 82. A stop 86 is formed at one end of the middle wall 78.

The first and second rails 74, 76 can be fixedly attached to each other such that the rails 74, 76 do not move relative to each other. The attachment of the rails 74, 76 can be accomplished with any suitable method, including, but not limited to, welding, mechanical lock, or rivets. As shown, the rails 74, 76 can include fastener openings 87 for receiving mechanical fasteners (not shown) for attaching the rails to each other. As illustrated, the first and second rails 74, 76 can be attached to each other in a position such that the middle walls 78 of the rails 74, 76 are adjacent to each other to arrange the first and second C-shaped channels 64, 66 in the back-to-back relationship. As such, the adjacent middle walls 78 can together define the partition 72 (see in FIG. 3), with the openings 84 facing opposite directions. It is noted that the adjacent middle walls 78 can be replaced with a single partition 72 between the first and second C-shaped channels 64, 66.

The rails 74, 76 can include one or more port(s) 88 formed through the middle wall 78, which provide for the passage of liquid through the middle wall 78. Soil can accumulate in or around the rail assembly 56, and the ports 88 allow liquid to pass through the track 62 to wash out the soil. As illustrated, the middle wall 78 can include multiple ports 88 which extend substantially along the length of the rail 74, 76.

The ports 88 in the rails 74, 76 can be positioned to at least partially overlap when the rail assembly 56 is in the first or cycle position, to provide for a continuous passage through the track 62. It is noted, however, that the ends of the first and second rails 74, 76 may be offset from each other in the first/cycle position, and, therefore, the ports 88 in the first and second rails 74, 76 may not be positioned at the same distances along each rail 74, 76, but rather may be relatively spaced based on the offset in order for the ports 88 to overlap when the rail assembly 56 is in the first/cycle position.

The rails 74, 76 can further include one or more glide rib(s) 90 (see FIG. 5 for an enlarged view) at least partially defining the C-shaped channels 64, 66, which function to maintain a space between the wheels 58, 60 and the middle wall 78 to ensure that the wheels 58, 60 do not contact the mechanical fasteners (not shown) received in the fastener openings 87, or the ports 88, thereby, ensuring that the rails 74, 76 slide smoothly over the wheels 58, 60. Each rail 74, 76 can include two vertically-spaced glide ribs 90 that extend horizontally along the length of the middle wall 78. The ribs 90 extend into the space defining the C-shaped channels 64, 66.

In the illustrated embodiment, the rail assembly 56 includes two tub mounting brackets 68. Each bracket 68 includes a vertically elongated flange 92 having two spaced openings 94 for receiving fasteners (not shown) for attaching the bracket 68 to the tub side wall 52, and a wheel interface 96 between the openings 94 for mounting the first wheel 58. The bracket 68 can also include a recessed portion 98 to allow clearance for the wheel 58 to rotate. Therefore, two first wheels 58 are fixed in place relative to the tub 18, but rotatable. Both wheels 58 are received in the first C-shaped channel 64, thereby allowing the first rail 74 to slide along the wheels 58 relative to the tub 18 and brackets 68. Since the second rail 76 is fixedly attached to the first rail 74, the second rail 76 will also slide relative to the tub 18 and brackets 68.

The rack mount 70 is mounted to one side of the rack 24 and includes two wheel interfaces 100 that each mounts one of the second wheels 60; therefore, two second wheels 60 are fixed in place relative to the rack 24, but rotatable. Both wheels 60 are received in the second C-shaped channel 66, thereby allowing the rack 24 to slide relative to the rails 74, 76, and the tub 18. The rack mount 70 can further comprise a rack height adjuster 102, as shown in the illustrated embodiment, that is configured to adjust the vertical height of the rack 24 relative to the track 62, thereby adjusting the vertical position of the rack 24 within the treating chamber 20. Such rack height adjusters are well known in the art, and will not be described further herein. Details of a suitable rack height adjuster can be found in U.S. Pat. No. 7,410,228 to Dickson et al., issued Aug. 12, 2008, which is incorporated herein by reference in its entirety. The rack mount 70 can alternatively be a stationary mount that couples the rack 24 with the track 62, but does not allow for height adjustment of the rack. The rack mount 70 can be flexible, for example, by being constructed of a flexible material such as polypropylene or acetal. The flexibility of the rack mount 70 is also affected by the geometry of the rack mount 70.

Each of the wheels 58, 60 include a wheel hub 104 rotatably coupled to an axle 106. In the illustrated embodiment, the first and second wheels 58, 60 have a similar construction, except that they are associated with different rails 74, 76; therefore, the features of the wheels 58, 60 will not be described separately herein, except where necessary for a full understanding of the embodiment of the invention. The axles 106 of the wheels 58, 60 are received by the wheel interfaces 96, 100, respectively, on the brackets 68 and rack mount 70.

FIG. 5 is a cross-sectional view through the rail assembly 56. The wheel hub 104 includes a central portion 108 having a bore 110 for receiving the axle 106, a rim 112 defining a peripheral rotational surface 114, and a neck portion 116 connecting the rim 112 to the central portion 108.

The axle 106 includes a first end 118 which is received in the wheel interface 96, 100 and has a flange 120 abutting an inner surface of the wheel interface 96, 100, and a second end 122 which is received in the bore 110 of the hub 104 and has a flange 124 abutting a surface of the central portion 108. The second end 122 is illustrated as having a slightly larger diameter than the first end 118, although the specific configuration of the axle 106 can be determined based on the configurations of the wheel interface 96, 100 and wheel hub 104.

The wheel hubs 104 are received within the C-shaped channels 64, 66, with the rims 112 rest on, and, therefore, moveable along, the lower wall 82 of the rails 74, 76. The glide ribs 90 confront the face of the rim 112, and prevent the wheel hubs 104 from touching the middle wall 78 of the rails 74, 76 in order to maintain a space between the wheel hubs 104 and the middle walls 78 to ensure that the wheels 58, 60 do not contact the mechanical fasteners (not shown) received in the fastener openings 87, or the ports 88, thereby, ensuring that the rails 74, 76 slide smoothly over the wheels 58, 60.

The materials for the wheel hub 104 and axle 106 can be selected to have a low coefficient of friction, thereby reducing the noise associated with and force required to rotate the wheel hub 104 relative to the axle 106. For example, the materials for the wheel hub 104 and axle 106 may be selected to have a coefficient of friction less than 0.25, more specifically, equal to or less than 0.15, or, even more specifically, ranging between 0.05 to 0.15.

One embodiment of the invention uses a metal axle 106, illustrated in the drawings as a metal rivet. The metal rivet can mount a plastic wheel hub 104 for rotational movement. The use of a metal rivet or axle 106 can further reduce the noise associated with sliding the rail assembly 56, because the part tolerances associated with a metal axle 106 are smaller than associated with previous plastic axles. Plastic axles are snap-fit with wheel hubs, which require larger part tolerances in order to accommodate the snap action. A larger part tolerance means that there are larger gaps between the axle and hub, which can produce a rattling noise when the wheel hub spins on the axle. Smaller part tolerance means that there are smaller gaps between the wheel hub 104 and axle 106, thereby reducing the rattling noise produced when the wheel hub 104 spins on the axle 106. Another reason that noise is reduced using a metal axle 106 is that prior plastic axles use glass or mineral fillers to stiffen the axle, which generate a lot of noise against the rotating wheel hub. One example of specific materials used for the metal axle 106 is stainless steel, and for the wheel hub 104 is acetal, also known as polyoxymethylene or POM. Stainless steel and acetal have a coefficient of friction of 0.15.

An exemplary operation of the rail system 54 will be described with respect to FIGS. 6-9. It will be apparent to one of ordinary skill that the operation can proceed in any logical order and is not limited to the sequence presented below. The following description is for illustrative purposes only and is not intended to limit the invention in any way.

FIG. 6 illustrates the upper rack 24 and rail system 54 in the first/cycle position, and FIG. 7 illustrates the relative position of the wheels 58, 60 within the track 62 of one of the rail assemblies 56 in the first/cycle position. In the first/cycle position, the wheels 58 on the brackets 68 are located as far forwardly as possible within the track 62, and the wheels 60 on the rack mount 70 are located as far rearwardly as possible within the track 62. The interaction between the rearward-most second wheel 60 on the rack mount 70 and the stop 86 on the second rail 76 prevents further rearward movement of the track 62 relative to the first wheel 58 and brackets 68. This position coincides with the upper rack 24 being completely received within the treating chamber 20 of the dishwasher 10, as shown for the lower rack 26 in FIG. 2.

FIG. 8 illustrates the upper rack 24 and rail system 54 in the second/loading position, and FIG. 9 illustrates the relative position of the wheels 58, 60 within the track 62 of one of the rail assemblies 56 in the second/loading position. When a user desires to move the rack 24 to the second/loading position, the user pulls the rack 24 forwardly, and the track 62 consequently slides over the wheels 58, 60, which rolls within the C-shaped channels 64, 66, along the lower wall 82 of the rails 74, 76. The track 62 slides until the stop 86 meets the first wheel 58 on the rearward bracket 68, as shown in FIG. 7. This position coincides with the upper rack 24 being at least partially out of the treating chamber 20 and at least partially overlying the door 22, as shown for the upper rack 24 in FIG. 2. In the second/loading position, the wheels 58 on the brackets 68 are located as far rearwardly as possible within the track 62, and the wheels 60 on the rack mount 70 are located as far forwardly as possible within the track 62.

The apparatus disclosed herein provides a rail system 54 for a dishwasher 10 that has improved performance over previous rail systems. One advantage that may be realized in the practice of some embodiments of the described systems and methods is that the rail system 54 may be smoother and require a more consistent and lower push/pull force to operate. Previous rail systems using two vertical wheel sets have the problem of inconsistent push/pull operating force, resulting from the upper wheel being loaded more than the lower wheel. Furthermore, such systems can result in rack twisting from the left and right rails not operating in sync. By using essentially side-by-side wheels 58, 60, the wheels 58, 60 are evenly loaded, and a lower and more consistent push/pull operating force is achieved. The right and left sides of the rack 24 will also push/pull more evenly. Another effect of the smoother and more evenly operable rail system 54 is the noise generating by the movement of the rack 24 into and out of the treating chamber 20 may be decreased.

Another advantage that may be realized in the practice of some embodiments of the described systems and methods is that external wheels are eliminated. Using external wheels, the tolerance stackup in the vertical dimension between the wheels, axles, and the rails results in a large gap between the components. The large gap allows more loose play of the rail system. Furthermore, the large gap allows the rails to twist more, which can result in a higher push/pull operating force. The rail system 54 of the present invention uses wheels 58, 60 that are received within C-shaped channels 64, 66. Therefore, the tolerance stackup in the vertical dimension includes only the space the outer diameter of one of the wheels 58, 60 and the inner diameter of one of the channels 64, 66, resulting in a smaller gap and less twisting.

Another advantage that may be realized in the practice of some embodiments of the described systems and methods is that part tolerances can be controlled as tight as manufacturing will allow in order to get a precision fit between the components of the rail system 54. The precision fit helps to eliminate noise generated by the operation of the rail system 54.

Another advantage that may be realized in the practice of some embodiments of the described systems and methods is that differences between the rack dimensions and the tub dimensions due to part tolerances can be accommodated by the selective use of flexible components, such as the tub side walls 52 and the rack mount 70. Providing flexible tub side walls 52 and/or rack mounts 70 decreases lateral deflection as well as vertical deflection of the rail assemblies 56. During operation of the rail system 54, the side walls 52 and/or rack mount 70 absorb at least some of the force associated with operation by flexing, rather than the force causing deflection of the rail assemblies 56.

Another advantage that may be realized in the practice of some embodiments of the described systems and methods is that soil accumulation is prevented by the provision of wash-out ports 88 in the track 62. The wash-out ports 88 provide a liquid passageway through the track 62 to wash out the soil.

Another advantage that may be realized in the practice of some embodiments of the described systems and methods is that the track 62 can include glide ribs 90 which prevent contact between the wheels 58, 60 and the wall 78 in order to maintain a space between the wheels 58, 60 and the mechanical fasteners (not shown) received in the fastener openings 87, or the ports 88, thereby ensuring that the rails 74, 76 slide smoothly over the wheels 58, 60.

Another advantage that may be realized in the practice of some embodiments of the described systems and methods is the use of a metal rivet to mount the hub 104 of the wheels 58, 60. Many current rail designs use a plastic axle that is snap fit to the wheel hub, which requires more gap or clearance to fit the parts together, which can produce a rattling noise when the wheel hub spins on the axle. The use of a metal rivet allows for the tolerance to be reduced, providing a smaller gap between the metal rivet of the wheel hub 104 and less noisy operation. Furthermore, the use of a plastic wheel hub 104 with the metal rivet or axle 106 provides for easier rotation than a plastic-on-plastic interface, since the materials can be selected to provide a low coefficient of friction; one particular pair of material discussed above is stainless steel and acetal.

While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation. Reasonable variation and modification are possible within the scope of the forgoing disclosure and drawings without departing from the spirit of the invention which is defined in the appended claims. 

What is claimed is:
 1. A dishwasher comprising: a tub at least partially defining a treating chamber and having at least one side; a rack for holding utensils for treatment within the treating chamber; a first wheel mounted to the at least one side of the tub; a second wheel mounted to the rack; and a track having a first C-shaped channel receiving the first wheel and a second C-shaped channel receiving the second wheel to slidably mount the rack to the tub, with the first and second C-shaped channels in a back-to-back relationship.
 2. The dishwasher of claim 1, further comprising a partition between the first and second C-shaped channels.
 3. The dishwasher of claim 2, wherein the partition comprises at least one port to provide for the passage of liquid through the partition.
 4. The dishwasher of claim 3, wherein the partition comprises multiple ports extending along the length of the track.
 5. The dishwasher of claim 4, wherein the partition comprises at least one first glide rib at least partially defining the first C-shaped channel and at least one second glide rib at least partially defining the second C-shaped channel.
 6. The dishwasher of claim 2, wherein the partition comprises a first wall at least partially defining the first C-shaped channel and a second wall at least partially defining the second C-shaped channel.
 7. The dishwasher of claim 6, wherein the first wall comprises at least one first port and the second wall comprises at least one second port at least partially overlapping the first port to provide for the passage of liquid through the partition.
 8. The dishwasher of claim 6, wherein the first wall comprises at least one first glide rib and the second wall comprises at least one second glide rib.
 9. The dishwasher of claim 1, wherein the track comprises a first C-shaped rail defining the first C-shaped channel and a second C-shaped rail defining the second C-shaped channel.
 10. The dishwasher of claim 9, wherein the first C-shaped rail comprises a first opening for receiving the first wheel and the second C-shaped rail comprises a second opening for receiving the second wheel, wherein the first and second openings face opposite directions.
 11. The dishwasher of claim 10, wherein the first C-shaped rail comprises a first elongated wall opposite the first opening and the second C-shaped rail comprises a second elongated wall opposite the second opening, and the first and second walls are adjacent to each other to form a partition between the first and second C-shaped channels.
 12. The dishwasher of claim 11, wherein the partition comprises at least one port formed in each of the first and second walls to provide for the passage of liquid through the partition.
 13. The dishwasher of claim 1, wherein the track comprises at least one first glide rib at least partially defining the first C-shaped channel and at least one second glide rib at least partially defining the second C-shaped channel.
 14. The dishwasher of claim 13, wherein the track comprises two spaced first glide ribs within the first C-shaped channel and two spaced second glide ribs within the second C-shaped channel.
 15. The dishwasher of claim 1, wherein the first and second wheels each comprise an axle and a wheel hub coupled with the axle, wherein the material for the axle and wheel hub is selected to have a coefficient of friction less than 0.25.
 16. The dishwasher of claim 15, wherein the axle is made from metal and the wheel hub is made from plastic.
 17. The dishwasher of claim 16, wherein the axle is made from stainless steel and the wheel hub is made from an acetal plastic.
 18. The dishwasher of claim 1, wherein the first and second wheels each comprise an axle and a wheel hub coupled with the axle, wherein the axle comprises a metal rivet.
 19. The dishwasher of claim 18, wherein the wheel hub is made from plastic.
 20. The dishwasher of claim 1, further comprising a bracket coupled to the at least one side of the tub, wherein the first wheel is fixedly mounted to the bracket to mount the first wheel to the at least one side of the tub.
 21. The dishwasher of claim 1, further comprising a height adjuster coupled to the rack, wherein the second wheel is fixedly mounted to the height adjuster to mount the second wheel to the rack.
 22. The dishwasher of claim 1, further comprising a stationary mount coupled to the rack, wherein the second wheel is fixedly mounted to the stationary mount to mount the second wheel to the rack.
 23. The dishwasher of claim 1, further comprising a flexible rack mount coupled to the rack, wherein the second wheel is fixedly mounted to the flexible rack mount to mount the second wheel to the rack.
 24. The dishwasher of claim 1, wherein the at least one side is flexible. 